1. Field of the Invention
The present invention relates to a quantizer with a sigma-delta modulator, an analog-to-digital converter including the same and a quantization method using the same, and more particularly, to a quantizer with a sigma-delta modulator, an analog-to-digital converter including the same and a quantization method using the same capable of obtaining a high signal-to-noise ratio with a relatively small number of comparators using a signal interpolator and a sigma-delta modulator.
The present invention is a result of a cooperation research between university and industry (research project no. 0414-20110009 titled “Research for Sigma-Delta Analog-to-Digital Converter).
2. Description of the Related Art
A quantizer is a device employed in an ADC (analog-to-digital converter) for converting an analog signal to a digital signal. Generally, a quantizer outputting an [n] bit PCM signal from an analog signal requires [2n−1] comparators. For instance, a quantizer outputting a four bit PCM signal from an analog signal requires fifteen comparators.
A quantizer having a small number of comparators has a poor SN (signal-to-noise) ratio due to large quantization error. Thus, in order to improve the SN ratio, the number of the comparators must be increased to enhance the resolution thereof. However, as the number of comparator increases, the power consumption of the quantizer also increases and an implementation of the quantizer becomes more difficult. Therefore, a quantizer capable of providing a high resolution and a superior SN ratio with a relatively small number of comparators is needed.